1. Technical Field
The invention relates generally to wood chippers. More particularly, the invention relates to a control system for controlling the feed of material into the wood chipper and the operation of the engine of the wood chipper. Specifically, the invention relates to such a control system which includes an engine-starting safety mechanism, a fuel-saving mechanism and a mechanism for automatically stopping or reversing the feed mechanism in response to an increased load upon the engine.
2. Background Information
Typically, wood chippers include an engine for powering a chipper and a hydraulic system for rotating a feed wheel which feeds wood material and the like into the wood chipper where the material is cut by a cutting assembly housed within the chipper. Safety regulations require that wood chippers have a feed control bar which runs along the top and sides of the feed chute of the wood chipper so that operators may easily control the direction of the feeding material by controlling the rotation of one or more feed wheels. The feed control bars typically have a forward feed position, a neutral position and a reverse feed position. Typically, the feed control bar actuates a directional control valve which directs hydraulic fluid to one or more feed motors to rotate the motors in a forward or reverse direction. This actuation is accomplished by linkages which are often fragile, hard to adjust and subject to wear and abuse. In addition, these traditional systems do not allow for automatic starting, stopping or reversing of the feed wheels. Instead, the operator must move the feed control bar to control the feed wheels. Dump valves have been added to allow an electronic control unit (ECU) to dump hydraulic fluid whenever the operational speed of the engine becomes too low. In addition, reversing valves have been added to allow the ECU to reverse the hydraulic flow to the feed motors. However, the wood chippers having these additions present a variety of poorly configured linkages and too many hydraulic valves and hoses. U.S. Pat. No. 6,830,204 granted to Morey discloses a reversing automatic feed wheel assembly for a wood chipper wherein an ECU controls a reversing valve in order to reverse the direction of the feed wheel in response to a reduced speed of or excessive load placed on the cutting assembly or engine of the wood chipper. However, said patent provides only for automatic reversal and subsequent automatic forward rotation of the feed wheel without the ability to maintain the feed wheel in a stopped or non-rotating state in response to an increased load on the cutting assembly or engine. In addition, the known prior art fails to provide a control system which allows a variety of functions related to controlling the feed wheel and the engine of the wood chipper. The present invention provides such a control system.